Yara Abdou, MD
Data are limited regarding the effect of interrupting radiation therapy for patients with BC. A retrospective study by Chow and colleagues looked at 35,845 patients with nonmetastatic triple-negative BC from the National Cancer Database who had received external beam radiation therapy as part of the management of their BC. The analysis showed inferior overall survival in patients with a longer duration of radiation treatment (hazard ratio 1.023; 95% CI 1.015-1.031) The more days of interruption, the higher the likelihood of mortality seen. In reference to 0-1 days of interruption, patients with 2-5 interrupted days (hazard ratio 1.069; 95% CI 1.002-1.140), 6-10 interrupted days (hazard ratio 1.239; 95% CI 1.140-1.348), and 11-15 interrupted days (hazard ratio 1.265; 95% CI 1.126-1.431) did worse. These findings should encourage further studies to explore ways to minimize treatment interruptions among patients with BC.
A lack of adherence to adjuvant endocrine therapy has been associated with increased mortality among women with BC. The retrospective study by Zheng and Thomas included 25,796 older women ( > 65 years old) diagnosed with stage I-III hormone receptor–positive BC and looked at a ssociations between adherence to and persistence with adjuvant endocrine therapy and mortality in this cohort. Their findings showed that the risk for all-cause mortality was reduced by 25% in patients with vs without cumulative adherence to endocrine therapy (hazard ratio 0.75; P < .001), although no association was seen with BC-specific mortality. Persistence with endocrine therapy, which was defined as having taken the treatment for ≥ 180 continuous days, was associated with 11% reduction in all-cause mortality and 37% reduction in BC-specific mortality. This study supports prior studies in highlighting the importance of endocrine therapy adherence among women with hormone-positive BC.
Tumor-infiltrating lymphocytes (TIL) are considered significant prognostic markers in patients with BC, although the prognostic effect of TIL in human epidermal growth factor reception 2 (HER2)–low BC has not been identified. A large-cohort, single-institution retrospective analysis by Sun and colleagues investigated t he prognostic role of TIL in HER2-low early-stage BC. The analysis included 1763 patients with early-stage BC who underwent surgery, of whom 429 patients were HER2+, 739 were HER2-low, and 595 were HER2-0. No differences in disease-free survival (DFS) were seen between the three cohorts. However, in patients with HER2-low BC, high (>10%) vs low (≤10%) TIL levels were associated with a 53% improvement in DFS overall (hazard ratio 0.47; P = .035), and a 58% improvement in DFS was seen for the hormone receptor–positive/HER2-low cohort (hazard ratio 0.42; P = .032).